Cable television is a system of delivering television programming to paying subscribers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fiber-optic cables. Historically, the cable network was predominantly a vehicle for delivering entertainment. With the advent of the Internet and the rise in demand for broadband two-way access, the cable industry began to seek new ways of utilizing its existing plant. Pure coaxial (“coax”) cable networks were replaced with hybrid fiber/coax networks (HFCs) using optical fiber from the head end to the demarcation with the subscriber coax (usually at a fiber node). Currently, a content-based network, a non-limiting example of which is a cable television network, may afford access to a variety of services including television, broadband Internet access, telephone service, and the like. There are also fiber networks for fiber to the home (FTTH) deployments (also known as fiber to the premises or FTTP.
One significant issue for a cable operator desiring to provide digital service is the configuration of its network. Designed for one-way delivery of broadcast signals, the existing cable network topology was optimized for downstream only (i.e., towards the subscriber) service. New equipment had to be added to the network to provide two-way communication. To reduce the cost of this equipment and to simplify the upgrade of the broadcast cable for two-way digital traffic, standards were developed for a variety of new cable-based services. The first of these standards, the Data Over Cable System Interface Standard (DOCSIS® standard), was released in 1998. DOCSIS® establishes standards for cable modems and supporting equipment. DOCSIS® (Data Over Cable Service Interface Specification) is a registered mark of Cable Television Laboratories, Inc., 400 Centennial Parkway Louisville Colo. 80027, USA, and may be referred to at some points herein in capital letters, without the ® symbol, for convenience.
There are many types of IP networks besides cable networks. Other wired IP networks include, for example, digital subscriber line (DSL), fiber to the home, fiber to the curb, and so on. Wireless IP networks include Wi-Fi, wireless ISP (Internet Service Provider), WiMAX, satellite interne, and mobile broadband.
One issue of concern to the operators of broadband networks is the unauthorized relocation of CPE devices (e.g., “cable boxes,” “set-top boxes” or STBs). For example, an unscrupulous individual might make unauthorized use of a STB. Prior approaches have focused on human intervention, detection of “rogue” devices with duplicate MAC addresses, and detection of “heartbeat” signals from a device.